Rack and pinion swing actuator for a backhoe

ABSTRACT

There is disclosed a backhoe having a readily removable swing actuator. The swing actuator comprises a reaction shaft receivable in a socket on a swing support bracket that is operative to non-rotatably retain the reaction shaft. A pinion is secured to the reaction shaft and a housing rotatably mounted on the reaction shaft and encompassing the pinion gear. A linear hydraulic motor is drivingly connected to the pinion gear and to the housing to operatively swing the housing around the reaction shaft. Means are provided for detachably coupling the housing to a pivotally mounted boom swing frame to transmit torque from the housing to the boom swing frame.

iinited States Patent [191 .1 ackson RACK AND PINION SWING ACTUATOR FORA BACKHOE [75] Inventor: James S. Jackson, Peoria, 111.

[73] Assignee: Caterpillar Tractor Co., Peoria, 111.

[22] Filed: Aug. 14, 1972 [21] Appl. No.: 280,587

[52] US. Cl. 74/89.17, 214/138 R [51] Int. Cl. F16h 27/02 [58] Field ofSearch 74/8917, 422; 37/103;

[56] References Cited UNITED STATES PATENTS 2,978,116 4/1961 Wells etal. 214/138 R 3,040,717 6/1962 Rumseym 74/89.l7

3,165,842 l/1965 Holopainen 214/138 R 3,278,046 10/1966 Shumake'r214/138 R 3,436,849 4/1969 Haynes 214/138 R 3,493,135 2/1970 Novotny214/138 R Primary Examiner-Benjamin W. Wyche Assistant ExamznerWesley S.Ratliff, Jr.

Attorney, Agent, or Firm--Fryer, Tjensvold, Phillips & Lempio [5 7]ABSTRACT There is disclosed a backhoe having a readily removable swingactuator. The swing actuator comprises a reaction shaft receivable in asocket on a swing sup- 5 Claims, 4 Drawing Figures .--'MENTEBAPR 16 1914V 13,803; 925

v sum 1 0f 4 RACK AND rumor: SWING ACTUATOR FOR A BACKHOE BACKGROUND OFTHE INVENTION The present invention relates to backhoes and pertainsmore particularly to a readily removable swing actuator for a backhoe.

Backhoes are normally mounted on a transversely supported frame attachedto the rear of a tractor or similar vehicle, and have a boom swing framepivotally mounted to the support frame for swinging movement about avertically disposed pivot axis. A hydraulic motor is normally secured tothe frame and coupled to the boom for swinging it about the pivotalaxis. Various types of hydraulic motors and drives are employed for suchapplication. One desirable form of such actuator comprises a linearhydraulic motor with a rack and pinion drive for transmitting thedriving force to the boom. These motors and drive arrangementsoccasionally break down and must be removed and replaced or removed andrepaired.

Known actuators of this type are generally built into the support frame,and are such an integral part of the support structure that the entireboom support structure must often be removed in order to remove orrepair the swing actuator. This requires that the backhoe be transportedto a shop that is equipped to perform this work. Such action and themanner of construction result in considerable down time in order toeffect such repair or replacement. This results in such repair beingextremely time consuming as well as expensive.

A swing actuator of the rack and pinion type which is built into thesupport structure is exemplified by U.S. Pat. No. 2,980,401, issued Oct.13, 1959 to H]. Schroeder. Anothertype of swing actuator having areadily detachable swing motor is illustrated or disclosed in U.S. Pat.No. 2,978,116, issued Apr. 4, 1961 to BL. Wells et al. This Wells patentillustrates one approach to solving the problem of expensive down time,should the hydraulic swing actuator fail.

SUMMARY AND OBJECTS OF THE INVENTION It is the primary object of thepresent invention to provide a swing actuator for a backhoe that isreadily detachable from the backhoe for repair or replacement withoutthe necessity for disassembly of the components of the backhoe.

Another object of the present invention is to provide a rack and piniontype swing actuator for a backhoe with novel coupling meansto permitready attachment and detachment to a backhoe without the necessity fordisassembly. I

A further object of the present invention is to provide a novel rack andpinion swing actuator and coupling means for detachably coupling theactuator for swing actuation of a backhoe.

In accordance with a primary aspect of the present invention, there isprovided a rack and pinion type swing actuator having a reaction shaftabout which the actuator swings to actuate or swing the backhoe linkage.The reaction shaft is slidably received in a socket on the swingactuator support wherein the reaction shaft is held in non-rotatableposition. The reaction shaft holding socket is built into the stationarysupport frame for the backhoe, and permits removal and replacement ofthe actuator without disturbing the relationship of any of the othercomponents of the backhoe assembly. Simple coupling means attaches orcouples the swing housing to the boom swing frame of the backhoe totransmit torque thereto.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects andadvantages of this invention will become apparent from the followingspecification when read in conjunction with the accompanying drawings,wherein:

FIG. 1 is a side elevational view of a backhoe embodying the principlesof the present invention;

FIG. 2 is a detailed elevational view of a pivotal support incombination with a swing actuator in accordance with the presentinvention;

FIG. 3 is a sectional view, taken generally along lines IIIIII of FIG.4; and,

FIG. 4 is a top view, with portions broken away, of the swing actuatorin accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to thedrawings, and particularly to FIG. 1, there is illustrated a swingactuator generally designated by the numeral 10, operatively connectedbetween a swing frame I2 and a stationary support frame 14 of a backhoe,generally designated by the numeral 16. The stationary support frame 14is secured in a suitable manner to' the back end of a suitable vehiclesuch as a tractor or loader 18.

The swing frame or support 12 is pivotally supported to the stationaryframe 14 for pivotal movement about a vertical axis, and supports thebucket linkage comprising a boom 20 and a stick 22, to which ispivotally supported a suitable bucket 24. These linkages are allmanipulated by the usual hydraulic rams as illustrated.

The frames 12 and 14, as best seen in FIG. 2, arepivotally connectedtogether by means of upper and lower brackets. The lower bracketgenerally comprises a rearward extending bracket member 26 receivedbetween the arms of a bifurcated bracket 28 and pivotally connectedtogether by means of a pivot pin 30. The upper bracket comprisesbifurcated member or bracket 32, extending rearwardly from stationarysupport member 14, and receiving the bracket member 34 extending forwardfrom the swing frame 12. The bracket mem bers are pivotally connectedtogether by means of a hollow pin or sleeve 36.

Turning now to FIG. 3, it is seen that the sleeve 36 extends throughbores 38 of the bifurcated member 32 and journals bracket member 34thereto by means of suitable bearing means 40. The sleeve 36 is formedwith an internal spline 42, and is non-rotatably secured to thebifurcated bracket member 32 by means of a flange 44 having a stub shaft46 with splines projecting into the spline bore 42 of the sleeve 36. Theflange 44 is non-rotatably secured to the bracket 32 by suitable meanssuch as bolts 48 and dowels or pins 50. The sleeve 36, together withflange 44, define a socket for receiving and non-rotatably supporting areaction shaft to be described.

Referring now to FIGS. 3 and 4, there is illustrated a preferredembodiment of the swing actuator of the present invention, comprisinggenerally a housing 52 having a removable cover 54 secured thereto in asuitable manner such as by screws or bolts 56. A reaction shaft 58 isrotatably mounted in the housing 52 such as by suitable bearing means 60and 62, and has suitable seal means 64.

The reaction shaft 58 includes splines 66 extending into and engagingsplines 42 of sleeve 36, so as to nonrotatably secure the shaft 58 withrespect to the stationary frame and bracket members 32. A pinion gear 68is non-rotatably secured in a suitable manner to the reaction shaft 58and is drivingly engaged by a reciprocable rack member 70. The rack 70is formed between a pair of pistons, only one of which is shown at 72,and which are reciprocally mounted in cylinders 74 and 76, which arecoaxially disposed in opposed relationship and suitably secured such asby means of bolts 78 and 80 to the housing 52. Suitable inlet ports 82and 84 are provided for the introduction of pressurized fluid into thecylinders 74 and 76 for operation of the pistons 72.

The housing 52 is provided with suitable brackets 86 and 88, extendingoutward therefrom and operatively connected such as by means of bolts 90and 92 to the swing frame 12. This bracket means provides appropriatemeans for operatively connecting the swing actuator to the swing frame12 for transmitting torque or force thereto for swinging the frame aboutits pivot point or pivot mountings.

As can be seen especially from FIG. 3, the swing actuator unit may becompletely removed simply by removing bolts 90 and 92 and lifting thehousing 52 upward to remove reaction shaft 58 from the socket defined bythe central bore of the sleeve 36. The removal of the actuating unit inno way affects the support by means of the pivot brackets of the supportor swing frame 12.

As can be readily seen from FIG. 4, the introduction of pressurizedfluid into either one of cylinders 74 or 76, forcing the rack 70 ineither direction with respect to the housing 52, will apply a force tothe reaction shaft 58 by way of pinion gear 68, swinging the housing 52about the reaction shaft. This swinging of the housing transmits forcedirectly to the swing frame 12 to likewise swing the backhoe boom aboutthe swing axis.

Thus, it can be seen from the above description that there is discloseda novel swing actuating apparatus and support assembly for a backhoethat permits the ready removal of the swing actuator without affectingsupport of the backhoe assembly. More specifically, there is disclosed arack and pinion swing actuator having a reaction shaft non-rotatablyreceived in a socket formed in stationary support means and operative totransmit torque to the boom.

While the present invention has been disclosed with respect to a singleembodiment, it is apparent that numerous changes and modifications maybe made in the illustrated structure without departing from the spiritand scope of the present invention as defined in the appended claims.

What is claimed is:

l. A pivotal support bracket assembly for pivotally supporting a backhoeboom for swinging movement about a vertical axis, said assemblycomprising:

stationary bracket and a movable bracket pivotally supported by aninternally splined sleeve to said stationary bracket;

a stationary splined reaction shaft slidably extending into said sleeveand non-rotatably coupled thereto:

a housing rotatably supported on said shaft;

a linear actuator mounted in said housing and drivingly connected tosaid shaft;

a stub shaft having splines formed thereon for engaging said splines insaid sleeve;

a flange formed on said stub shaft for securing said shaft to saidstationary bracket; and,

means operatively connecting said housing to said movable bracket.

2. A detachable swing actuator assembly for a backhoe and the like, saidassembly comprising:

a vertically oriented swivel mount comprising a fixed bifurcated firstbracket comprising upper and lower spaced members having a verticallyoriented cylindrical bore formed therein;

a hollow pin having internal splines formed therein mounted in said boreand pivotally mounting a second bracket member to said first bracket;

means non-rotatably securing said hollow pin to said bracket;

a swing actuator comprising a housing, a reaction shaft including apinion rotatably mounted in said housing and a linear hydraulic actuatorincluding a rack drivingly connected to said reaction shaft;

said reaction shaft having a splined portion extending into andnon-rotatably connected by cooperative engagement of said splines tosaid hollow pin; and,

means connecting said housing to said second bracket. 3. A swing driveactuator for a backhoe comprising:

a bracket for pivotally supporting a boom for swinging movement about avertical axis;

said bracket including means defining a nonrotatable socket;

a reaction shaft fixedly receivable in said socket;

a pinion coupled to said reaction shaft;

a housing rotatably mounted on said shaft and enclosing said pinion;

a linear hydraulic motor attached to said housing and including a rackdrivingly connecting said hydraulic motor to said pinion; and,

means for connecting said housing for transmitting torque to a boompivotally supported in said bracket.

4. A swing drive actuator for a backhoe comprising:

a bracket for pivotally supporting a boom for swinging movement about avertical axis; said bracket including a pin having an axial boredefining a non-rotatable socket having splines formed therein;

a flange securing said pin to said bracket;

a reaction shaft fixedly receivable in said socket;

a pinion coupled to said reaction shaft;

a housing rotatably mounted on said shaft and enclosing said pinion;

a linear hydraulic motor attached to said housing and including a rackdrivingly connecting said hydraulic motor to said pinion; and,

means for connecting said housing for transmitting torque to a boompivotally supported in said bracket.

5. A swing drive actuator for a backhoe comprising:

a bracket for pivotally supporting a boom for swinging movement about avertical axis:

said bracket including a pin having an axial bore defining anon-rotatable socking having splines formed therein;

said pin comprises a pivotal support for said bracket;

a reaction shaft fixedly receivable in said socket;

bracket.

UNITED STATES P TENT oFFICE f: CERTIFICATE OF CURRECTION Patent No.3,803,925 Dated Anril 16. 1974 mventorm) James 5 Jackson,

i It is certified that error appears in the above-identified patent andthat said Letters Patent are'hereby corrected as shown below:

Claim 5, line -6, "soaking" is corrected to read -socket-- Signed andsealed this 8th day of October 1974 (SEAL) Attest: McCOY M. GIBSON 'JR.c. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PC4050(10-69) sco c 603.75-p59 :r us, eovzauuzn r PRINTING OFFICE: [969o-ass-au

1. A pivotal support bracket assembly for pivotally supporting a backhoeboom for swinging movement about a vertical axis, said assemblycomprising: stationary bracket and a movable bracket pivotally supportedby an internally splined sleeve to said stationary bracket; a stationarysplined reaction shaft slidably extending into said sleeve andnon-rotatably coupled thereto: a housing rotatably supported on saidshaft; a linear actuator mounted in said housing and drivingly connectedto said shaft; a stub shaft having splines formed thereon for engagingsaid splines in said sleeve; a flange formed on said stub shaft forsecuring said shaft to said stationary bracket; and, means operativelyconnecting said housing to said movable bracket.
 2. A detachable swingactuator assembly for a backhoe and the like, said assembly comprising:a vertically oriented swivel mount comprising a fixed bifurcated firstbracket comprising upper and lower spaced members having a verticallyoriented cylindrical bore formed therein; a hollow pin having internalsplines formed therein mounted in said bore and pivotally mounting asecond bracket member to said first bracket; means non-rotatablysecuring said hollow pin to said bracket; a swing actuator comprising ahousing, a reaction shaft including a pinion rotatably mounted in saidhousing and a linear hydraulic actuator including a rack drivInglyconnected to said reaction shaft; said reaction shaft having a splinedportion extending into and non-rotatably connected by cooperativeengagement of said splines to said hollow pin; and, means connectingsaid housing to said second bracket.
 3. A swing drive actuator for abackhoe comprising: a bracket for pivotally supporting a boom forswinging movement about a vertical axis; said bracket including meansdefining a non-rotatable socket; a reaction shaft fixedly receivable insaid socket; a pinion coupled to said reaction shaft; a housingrotatably mounted on said shaft and enclosing said pinion; a linearhydraulic motor attached to said housing and including a rack drivinglyconnecting said hydraulic motor to said pinion; and, means forconnecting said housing for transmitting torque to a boom pivotallysupported in said bracket.
 4. A swing drive actuator for a backhoecomprising: a bracket for pivotally supporting a boom for swingingmovement about a vertical axis; said bracket including a pin having anaxial bore defining a non-rotatable socket having splines formedtherein; a flange securing said pin to said bracket; a reaction shaftfixedly receivable in said socket; a pinion coupled to said reactionshaft; a housing rotatably mounted on said shaft and enclosing saidpinion; a linear hydraulic motor attached to said housing and includinga rack drivingly connecting said hydraulic motor to said pinion; and,means for connecting said housing for transmitting torque to a boompivotally supported in said bracket.
 5. A swing drive actuator for abackhoe comprising: a bracket for pivotally supporting a boom forswinging movement about a vertical axis: said bracket including a pinhaving an axial bore defining a non-rotatable socking having splinesformed therein; said pin comprises a pivotal support for said bracket; areaction shaft fixedly receivable in said socket; a pinion coupled tosaid reaction shaft; a housing rotatably mounted on said shaft andenclosing said pinion; a linear hydraulic motor attached to said housingand including a rack drivingly connecting said hydraulic motor to saidpinion; and, means for connecting said housing for transmitting torqueto a boom pivotally supported in said bracket.